WO2004072339A1

WO2004072339A1 - Thread guide device for a ring spindle

Info

Publication number: WO2004072339A1
Application number: PCT/EP2004/001302
Authority: WO
Inventors: Peter Artzt; Jürgen Schneider; Theo GRÜN
Original assignee: Deutsche Institute Für Textil- Und Faserforschung Stuttgart Stiftung Des Öffentlichen Rechts
Priority date: 2003-02-14
Filing date: 2004-02-12
Publication date: 2004-08-26
Also published as: DE10306475A1; CN1751145A; DE502004008685D1; EP1592828A1; JP2006517503A; EP1592828B1; JP4972399B2; CN100510219C

Abstract

The invention relates to a rotating thread guide (1) for ring spinning frames, said thread guide being arranged at a distance (4) above the upper end (31) of the ring spindle (3) and being coupled to the ring spindle (3) by means of a magnetic field of force, in such a way that the thread guide (1) rotates at the same rotational speed as the ring spindle (3). The inventive thread guide is embodied as a twisting element (11) comprising a driving element (13) for the continuous threads.

Description

Thread guide device for Rinqspindel

The invention relates to a arranged between Strec plant output and ring spindle thread guide device for ring spinning machines, which has a swirl element which is arranged at a distance above the upper end of the ring spindle and is coupled to the ring spindle via a magnetic force field, so that the swirl element with the same speed how the ring spindle rotates.

It is a known fact that the threads on the ring spinning machine break mainly between the drafting device and the thread guide in the so-called spinning zone. In this area, the fuse which emerges from the drafting system has not yet hardened to the point that it is able to withstand any tension in the thread tension. In addition, the conventional thread guide, the so-called thread guide eye, partially hinders the rotation propagation into the spinning zone.

In order to solve this problem, experts have been making numerous proposals for several decades, for example, it has been proposed to place so-called crowns on the ring spindle in order to make the swirl from the rotor rotating on the ring more effective towards the spinning triangle. in order to achieve better solidification of the fuse emerging from the drafting system in the critical area. In these spindle attachments, the thread lies in the teeth of the crown and is taken along by it, however, the thread on the crown must make the same backward movement as the runner on the spinning ring, which, depending on the winding and the winding speed, lags behind the peripheral speed of the spindle. The thread jumps backwards from point to point according to the lag of the runner. The resulting friction leads to yarn damage and roughening of the yarn, which is undesirable. In addition, each jump creates a bump on the runner. This crown spindle attachments therefore have one large runner wear. With the so-called spinning finger as an attachment to the ring spindle, the crown prongs are avoided, the spinning finger is smooth and therefore roughen the yarn less. However, the spinning finger works practically like a crown with a point around which the yarn runs. This means that the jump is much bigger, almost one turn. The runner stops briefly at this moment of jumping and is then accelerated again. This spinning finger solution therefore leads to large thread runs. In addition, the spinning finger cannot be balanced, which is why special spindle bearings are required to withstand this imbalance.

In order to avoid these disadvantages, it has been proposed to provide a rotating thread guide. This rotating thread guide consists of a ball-bearing swirl element, which is expediently made of ceramic, which is mounted above the upper spindle part of the ring spindle independently of it on the machine frame, and magnetically coupled to the ring spindle via permanent magnets arranged in the spindle head and in the swirl element and upon rotation the same is taken away. The spindle speed is transmitted synchronously to the swirl element through this magnetic coupling. This known device (Textilpraxis International 1982, January, pages 19 and 20) gives the thread in the spinning zone an incorrect rotation by touching the thread as it passes through the swirl element and the edge of the spindle upper part. However, it has been shown that the effect of this rotating thread guide is unsatisfactory since the thread is exposed to considerable slippage when it is touched, so that the false wire production is unstable and therefore unsatisfactory. Added to this is the intermittent mode of operation, since the thread only lies completely against the friction body and experiences a torque only during the fraction of a balloon or rotor revolution. In addition, the effect of the known device is strongly dependent on the course of the thread. A really significant reduction in thread tension and / or thread breaks has not been shown. Apart from the threading problems the thread breakage problem on the ring spinning machine cannot generally be solved by the rotating thread guide. It has also proven to be a disadvantage that in the magnetic coupling of the spindle and the thread guide, a controlled thread guide movement has to be dispensed with from the outset.

From DE 196 29 787 A1 a rotating thread guide is known, which is arranged as a twist device between the usual thread guide above the spindle and the ring traveler directly above the ring spindle, a rotating body being carried by the spindle by means of a magnetic coupling. The fiber structure is introduced centrally and laterally out of the rotating body, from where the fiber structure extends in a balloon to the ring traveler. Alternatively, the rotating body should have a helical channel and be driven slower or faster than the spindle regardless of the spindle. This is intended to temporarily overlay a small false wire on the fiber structure. This known device has also not been able to be introduced in practice, since the external drive is too complex and, moreover, there is no defined rotation.

The object of the invention is to avoid these disadvantages of the prior art and to provide a device which is able to ensure better and defined propagation of rotation up to the spinning triangle. The device should be simple and easy to use at the same time.

This object is solved by the features of claim 1.

By designing the thread guide device according to claim 1, a defined entrainment of the thread by the swirl element takes place, so that the thread is given defined rotation in the critical area between the thread guide device and the drafting device. The upswing is continuous and effects bumpless. The inevitable entrainment of the thread eliminates slippage and unpredictability as in the case of entrainment of friction and thus also the influences of the entry angle into the thread guiding device. The wrapping around the core of the swirl element acts like a brake, so that voltage peaks starting from the rotor and the balloon are damped and cannot have an effect in the sensitive area between the thread guide device and the drafting system. The thread bale is reduced so that balloon constriction rings are not necessary. By wrapping the core against the direction of rotation of the spindle, the rotation imparted by the spindle is increasingly generated between the thread guide device and the drafting system outlet. The rotation propagates until just before the drafting system exit and leads to a rapid solidification of the fiber sliver emerging. The driver is expediently designed as a helix, since the helix prescribes a defined wrap around the thread. Operator errors are prevented. Depending on the size of the winding angle with which the thread wraps around the core of the driver, the braking effect can be reduced or increased. The helix angle α of the helical coil is expediently between 360 ° and 720 °, preferably approximately 540 °, in order to achieve optimal damping. It can also be used to influence the rotation in the area between the thread guide device and the drafting device outlet. For good entrainment of the thread without roughening it, the upper and lower ends of the helical coil 13 are designed as an edge which lies in a plane perpendicular to the axis of rotation of the helical coil and is appropriately rounded.

The encapsulation of the twist element not only protects the twist element and the thread path, but also prevents winding or knotting of the thread if the thread breaks. In addition, this encapsulation enables automatic threading using suction air, which leads to savings in operating times when removing threads. To avoid accumulation of flights and to dissipate frictional heat, it can be be ßig to provide the encapsulation of the swirl element with ventilation openings.

The eccentric arrangement of the thread inlet bore has surprisingly meant that there is no balloon formation between the thread guide device and the drafting system. The eccentricity suitably depends on the radius of the core of the driver. The central arrangement of the thread outlet bore ensures vibration-free twist distribution. In order to avoid excessive thread tensions, it has proven to be expedient to arrange the thread guiding device centrally at a certain distance from the upper end of the sleeve fitted onto the ring spindle above the end of the ring spindle. A distance of at least 25 millimeters has proven to be favorable. As a rule, a distance approximately the size of the radius of the spinning ring has proven itself.

The pivotability of the thread guide device from an operating position to an operating position not only enables the manual or mechanical removal of the cops without problems, but also serves to maintain and keep the thread guide device clean. In the operating position, the thread guide device can expediently be coupled to a suction device, which can simultaneously actuate the thread guide device by moving it into the operating position. In this way, the thread guiding device is cleaned of flight and threaded through the suction device of the thread for re-spinning into the thread guiding device. By cranking the holder of the thread guide device, the use of balloon constriction rings rigidly attached to the ring bench is made possible.

Further details of the invention will be described with reference to the drawings. Show it:

Figure 1 shows the thread guide arrangement according to the invention in connection with the ring spindle and a suction device; Figure 2 shows the driver designed as a helix according to Figure 1;

Figure 3 is a plan view of the driver according to Figure 2;

FIG. 4 shows a plan view of the housing according to FIG. 1;

Figure 5 shows another embodiment of the thread guide device according to the invention.

Figure 6 shows the spinning station of a ring spinning machine with a further embodiment of the thread guide device.

Figure 7 shows an embodiment of the housing of the thread guide device with ventilation openings in section.

In Figure 1, an embodiment of a rotating thread guide device is shown in section. It consists of a housing 2 with an eccentrically arranged yarn inlet opening 21, the swirl element 11 rotatably mounted in a ball bearing 16 with a centrally arranged thread outlet opening 22. In the swirl element 11, a driver 13 is mounted and connected to it in a rotationally fixed manner, so that this driver 13 rotates together with the swirl element 11. The driver 13 has a core 13 'which extends coaxially to the axis of rotation and around which a thread F which extends from the spindle 3 to the drafting system outlet can be looped. On this core 13 'there is an upper edge 15 and a lower edge 15', against which the thread passing through the thread guide device 1 rests and is carried along when the twist element 11 rotates.

The swirl element 11 with the driver 13 is expediently encapsulated by a housing 2 to protect the thread running through the swirl element 11 and to avoid winding or knots in the event of thread breakage: the housing 2 is placed stationary on the bearing ring 17, which serves to receive the ball bearing 16. The bearing ring 17 is received by a holder 18 which is pivotable about a hinge 19. As a result, the thread guiding device 1 can be pivoted up into the operating position 1 'shown in dashed lines, so that the head of the spindle 3 is free and accessible for the removal of the cops and reinserting sleeves 4.

A further suction device 5 in the form of a tubular profile is arranged on the ring spinning machine parallel to the usual sliver suction arranged under the drafting rollers. Each spinning station is assigned a suction opening 51 on this tube 5, against which the thread inlet opening 21 of the thread guiding device 1 bears in the operating position 1 ', so that suction air 5 is sucked through the thread guiding device 1 by the suction device 5. This suction serves on the one hand to keep the thread guiding device 1 clean of flight and similar loose deposits. On the other hand, the thread F carried up by the spindle 3 can be placed in front of the central thread outlet opening 22 so that it is sucked into the thread guiding device 1 and thus threaded. For re-spinning, the thread guide device 1 is folded down from its operating position 1 'into the operating position. The thread F extending from the thread inlet opening 21 into the suction opening 51 is taken up for the start of the spinning process and is applied to the drafting device in a known manner.

The suction opening 51 is expediently visible and closable by the movement of the thread guide device 1 in order to avoid unnecessary air consumption in the operating position. This can be done in a simple manner in that a cam is arranged on the thread inlet opening 21 of the thread guide device 1, which presses on the closure of the suction opening 51 or actuates it in another way, so that the suction device 5 is activated when the thread guide device is in the operating position 1 " to the Mamming opening 51 creates, and the suction opening 51 is closed again when the thread guide device 1 is pivoted back into its operating position.

The part of the swirl element 11 facing the spindle 3 is designed as a magnet and forms a magnetic coupling with the head 31 of the spindle 3, which is also equipped with permanent magnets, so that the swirl element 11 rotates at the same speed as the spindle 3. The distance of the spindle head 31 from the swirl element 11 is determined in a known manner by the magnetic field which is necessary to ensure that the swirl element 11 is carried along by the spindle 3. As a rule, this distance is about 5 to 10 mm.

In the simplest embodiment, the driver 12, as shown in FIG. 5, is designed as a cross or T and consists of the core 12 'around which the thread F passing through the thread guide device 100 is looped and an edge 14 which acts as a crossbar Core 12 'is attached. This edge 14 takes the thread F entering through the thread inlet opening 24 and gives it rotation analogous to the spindle speed. The thread leaves the thread guide device 100 via a thread outlet opening 23 in the twist element 10. As in the embodiment according to FIG. 1, the twist element 10 is rotatably mounted in a ball bearing 16 in the bearing ring 17 on the holder 18. The drive is carried out by the magnetic coupling described above between the spindle head 31 and the swirl element 10.

In order to prevent the full tension of the balloon from being transferred to the spinning zone between the thread guide device 100 and the drafting device outlet, the thread is looped around the core 12 ′ of the driver 12. Depending on the friction value of the surface of this core 12 'of the driver 12, the looping takes place once or twice in order to obtain the desired damping. In the case of this simple embodiment according to FIG. 5, such a wrap requires an increased amount of time for manual threading through the loading. service required. The housing 20 must also be removable for this purpose. In addition, only whole or half loops are possible. A finer gradation would be provided if a further crossbeam was provided as the lower driver edge, for example offset by 90 ° to the edge 14.

In the embodiment in FIG. 1, the driver 13 is therefore designed as a helix, as shown in detail in FIG. The screw helix 13 has an edge 15 at its upper end and an edge 15 'at its lower end, via which the thread F runs into the screw helix 13 or out of the screw helix. The winding angle α of the helical coil 13 is precisely defined by the two edges 15 and 15 'and the wrap around the core 13' is automatically determined. As described above, the thread is sucked in, automatically engages in the course of the helical coil 13, and the desired wrap is produced. In order to ensure gentle thread running during operation and easy threading, the edges 15 and 15 'are preferably designed as a rounded web.

As a result of the heavy stress caused by the running of the thread, it is expedient to produce this helical coil 13 from ceramic or from metal with a wear-resistant sinter coating. Via the sintered coating or the surface of the ceramic part, it is possible to give a certain friction value μ of the surface and thus to determine the desired damping in addition to the wrapping. Experiments have shown that sufficient damping is achieved with a wrap angle α of at least 360 °. A loop of α = 540 ° (approximately 1 1/2 loops) has proven to be optimal.

The damping acts in the following way: The friction of the thread as a result of the wrap on the driver 12 or 13 makes it stronger Train from the thread balloon required, which has the consequence that the balloon is smaller. This eliminates the need for balloon constriction rings and their movement control. At most, they are still necessary for the winding of the cop attachment. On the other hand, the tension in the spinning zone between the thread guide device and the drafting system is significantly reduced, since this is retained by the friction on the driver 12 or 13. In particular, tension peaks, which are formed by runners and balloons and which have often led to thread breaks, are eliminated from the spinning zone.

When the rotation is given by the driver 12 or 13, the looping on the driver has an inhibiting effect on the propagation of the rotation in the direction of the thread balloon / spinning ring. In the thread part F '(FIG. 6) there is a rotation jam, through which the fibers emerging from the drafting system receive rotation and are immediately solidified. It has been shown that the rotation propagation in the direction of the drafting system exit depends on the direction in which the core 12 'or 13' of the driver 12 or 13 is wrapped. A wrap against the direction of rotation of the spindle 3 has a promoting effect for the propagation of the rotation in the direction of the drafting device exit. It is therefore important for the operator to ensure that the wrap is not only in the desired wrap angle, but also in the correct direction. When using the driver 13 according to FIG. 2, not only the desired wrap angle α, but also the correct direction is automatically carried out when threading through the helical formation. Operating errors are excluded.

The functioning of the thread guide device is as follows: The from the

Drawstring thread F 'runs through the thread inlet opening 21 or 24 into the housing 2 of the thread guide device 1 or the housing

20 of the thread guide device 100 and leaves through the yarn outlet opening 22 or 23 the thread guide. The edges 15 and 15 'or the driver 12 with the edge 14 which surround the driver 13 capture the thread F which extends through the housing 2 or 20 and impart this to the driver by rotating the spindle speed, since the spindle 3 has the swirl element via the magnetic coupling 10 or 11 drives. The thread F leaving the twist element 10 or 11 runs over the thread balloon in usually under the rotor 63 rotating on the spinning ring 62 for winding onto the sleeve 4. Since the rotor 63 remains behind the angular velocity of the spindle 3 by the winding, it rotates this amount again reduces the real twist which the thread F 'has received in the spinning zone. It is advantageous, however, that for solidification the fuse emerging from the drafting device in the spinning zone is given a higher rotation which is to be measured exactly by the driver 12 or 13 and which propagates into the spinning triangle. This leads to an exact distribution of twist acting on the fiber structure as soon as it leaves the drafting system. Jumping over crown prongs or the like is eliminated, as are the imponderables of swirling due to friction.

Measurements have shown that the thread guide device according to the invention achieves 109% of the rotation in the critical area between the drafting device outlet and the thread guide device in the thread F 'at a wrap angle of 360 ° in front of the spinning triangle, and even 115% turn at a wrap angle of 720 ° to the target twist in the finished yarn. In contrast, only 84% of the target rotation in front of the spinning triangle could be achieved with the conventional thread guide with balloon constriction ring. This means that the spinning triangle is reduced and the emerging fiber structure is immediately solidified in this critical area. Therefore, thread breaks hardly occur in this area. These measurement results also show that the size of the wrap angle is of great importance, although this is of course also subject to limits, since the wrap angle α makes the required Traction on the thread balloon side becomes too high and thread breaks occur in the runner area. Taking advantage of this knowledge, an almost thread-break-free spinning can be achieved by coordinating the wrap angle α and the dimensions of the driver 12 or 13. In the tests carried out, a wrap angle of α = 540 ° with a radius of the core 13 'of 1.5 mm and a height of the screw coil 13 of 15 mm has been found to be particularly expedient.

The difference between the angular velocity of the spindle 3 and the angular velocity of the rotor 63 is compensated for after the thread F has left the twist element 11 or 10 in the direction of the rotor / spinning ring. The thread F can move freely in the space between the spindle head 31 and the swirl element 10 or 11, so that this compensation takes place continuously, in contrast to the measures for propagating rotation known from the prior art. The thread F should be able to move as freely as possible, although it may touch the spindle head 31, but should not rub against it in such a way that a torque is exerted on the thread, in particular not in the untwisting direction. It is therefore necessary to maintain a distance h between the upper edge of the sleeve 4 and the thread guiding device 1 or 100, so that a sufficiently large balloon is also present in the uppermost position of the ring rail 6 and so that the spindle head 31 does not touch or only touches little becomes. On the other hand, the magnetic coupling of the thread guiding device 1 or 100 causes the spindle head 31 at a short distance of about 5 to 10 millimeters in order to guarantee the entrainment of the swirl element 10 or 11. It is therefore necessary to extend the spindle beyond the end of the sleeve 4, for example by at least 25 mm. Depending on the diameter of the spinning ring and the resulting thread balloon, it has proven expedient to provide an extension at least by the amount of the spinning ring radius. In the embodiment in FIG. 5, a central thread inlet bore 24 is shown, while in the embodiment in FIG. 1 the thread inlet bore 21 is arranged eccentrically. Surprisingly, it has been shown that the eccentric thread inlet bore 21 is more advantageous than a central thread inlet bore 24 since it avoids ballooning between the thread guide device 1 or 100 and the drafting device outlet. The eccentricity e of this thread inlet bore 21 to the axis of rotation of the driver 13 should correspond approximately to the radius of the core 13 'of the helical coil 13 (FIG. 4). In order to avoid balloon formation in the embodiment according to FIG. 5, the thread inlet bore 24 would have to be arranged eccentrically to the axis of rotation of the driver 12 around the radius of the core 12. In contrast, a central thread outlet opening, as shown in FIG. 1, is more advantageous than an eccentric one 5, since vibrations and thus tension peaks due to vibrations are avoided by the central guidance of the thread balloon. In order to enable this central thread exit, the thread F wrapped around the core 13 'is removed from the lower edge 15' of the screw spiral 13 in a free space 25 of the swirl element 11 is guided under the driver 13, through which the thread F enters the central thread outlet bore 22.

In Figure 6, the entire spinning station including the spindle 3 with its bearing 32, as well as the ring bench 6 and the spinning ring 62 is shown schematically. In this embodiment, it is provided that balloon constriction rings 61 are rigidly attached to ring bank 6. Since, as a result of the thread guide device according to the invention, balloon constriction rings 61 are required at most when winding the cop attachment, a separate movement control can be dispensed with. When winding onto the tip of the head, however, the balloon constriction ring 61 would be prevented from moving by the holding of the thread guiding device 1 or 100. A cranked holder 181 is therefore provided for the thread guiding device 1 or 100, which extends through the balloon constriction ring 61 so that the distance for the magnetic coupling of the twist element 10 or 11 is made possible. on the other hand, the balloon constriction ring 61 with the ring bench 6 can assume the upper position necessary for the winding, which is indicated by dashed lines in FIG. 6.

FIG. 7 shows a further embodiment of a housing 200 of the thread guiding device 1 or 100. In order to avoid accumulation of flight within the housing 200 and also to dissipate heat which can arise due to the thread friction or the ball bearing, ventilation openings 26 are provided.

The thread guide device according to the invention has been described with reference to two embodiments. However, the invention is not limited to the embodiments described, for example the driver 12 or 13. Other designs of the driver, for example also as an eyelet or in a similar manner, realize the inventive idea and the function achieved in the same way. The invention is also not limited to the application described in conventional ring spinning. The invention can also be used with considerable advantage in the so-called "Siro spinning", in which two warped fiber lunches which run out of the drafting device are spun into a twisted thread. Here, for example, by using the invention described above, the triangle between the two converging fibers at the exit of the drafting system could be shortened by half.

Claims

Patent claims

1. Between the drafting device and the ring spindle arranged thread guide device for ring spinning machines, which has a swirl element which is arranged at a distance above the upper end of the ring spindle and is coupled via a magnetic force field to the ring spindle, so that the swirl element with the same speed as the ring spindle rotates, characterized in that the swirl element (10; 11) has a driver (12; 13) which consists of a core (12 '; 13') extending coaxially to the axis of rotation, around which the thread passing through the thread guide device can be looped, and a driver edge (14; 15; 15 ') arranged on the core (12'; 13 ').

2. Device according to claim 1, characterized in that the core (12 '; 13') is wrapped in the thread in the opposite direction to the spindle rotation.

3. Device according to one of claims 1 or 2, characterized in that the driver is designed as a screw coil (13).

4. The device according to claim 3, characterized in that the winding angle α of the helical coil (13) is greater than 360 °, preferably about 540 °.

5. The device according to one or more of claims 2 to 4, characterized in that the pitch of the screw coil (13) is opposite to the direction of rotation of the spindle.

6. The device according to one or more of claims 1 to 5, characterized in that the edge (14; 15; 15 ') of the driver (12; 13) lies in a plane perpendicular to the axis of rotation of the Dralielemenf.es (10; 11) ,

7. The device according to one or more of claims 1 to 6, characterized in that the edge (14; 15; 15 ') of the driver (12; 13) is designed as a rounded web.

8. The device according to one or more of claims 1 to 7, characterized in that the upper and the lower end of the helical coil (13) is designed as an edge (15; 15 ').

9. The device according to one or more of claims 1 to 8, characterized in that the thread guide device (1; 100) has a housing (2; 20) in which the swirl element (10; 11) is rotatably arranged.

10. The device according to claim 9, characterized in that the housing (2) has a thread inlet bore (21) which is arranged eccentrically to the axis of rotation of the swirl element (11).

11. Device according to one of claims 9 or 10, characterized in that the thread inlet bore (21) is arranged in a plane perpendicular to the axis of rotation of the swirl element (10; 11).

12. The device according to one or more of claims 9 to 11, characterized in that the housing (200) has ventilation openings (26).

13. The device according to one or more of claims 9 to 12, characterized in that the swirl element (10) has a thread outlet bore (23) which is arranged centrally.

14. The device according to one or more of claims 10 to 13, characterized in that the eccentricity (e) corresponds approximately to the radius of the core (12 '; 13') of the driver (12; 13).

15. The device according to one or more of claims 1 to 14, characterized in that the thread guide device (1; 100) at a certain distance (h) to the upper end of the sleeve (4) attached to the sleeve (4) centrally above the end (31) the ring spindle (3) is arranged.

16. The apparatus according to claim 15, characterized in that the annular spindle (3) protrudes at least 25 mm beyond the upper end of the sleeve (4).

17. Device according to one of claims 15 or 16, characterized in that the annular spindle (3) protrudes at least by the radius of the spinning ring over the upper end of the sleeve (4).

18. The device according to one or more of claims 1 to 17, characterized in that the thread guide device (1; 100) is pivotable from its operating position into an operating position (1 ').

19. The apparatus according to claim 18, characterized in that the thread guide device (1; 100) in the operating position (1 ¹ ) with. a suction device (5) can be coupled.

20. Device according to one of claims 18 or 19, characterized in that the thread guide device (1; 100) actuates the suction device (5) by its movement into the operating position (1 ').

21. The device according to one or more of claims 1 to 20, characterized in that the thread guide device (1; 100) is attached to a cranked holder (181) so that a balloon constriction ring (61) attached to the ring bench in its uppermost Limit position can move over the thread guide device (1; 100).

22. Driver for a rotating thread guide device for ring spinning machines according to one or more of claims 1 to 21, characterized in that the driver (12; 13) consists of wear-resistant material.

23. Driver according to claim 22, characterized in that the driver (12; 13) has a wear-resistant coating.

24. Driver according to one of claims 22 or 23, characterized in that the driver (13) is designed as a helical coil.

25. Driver according to claim 22, characterized in that the winding angle α of the helical coil (13) is 360 ° to 720 °.

26. Driver according to one or more of claims 22 to 25, characterized in that by the grain of the material, the coefficient of friction μ

^• Surface of the driver (12; 13) is determined.

27. Driver according to one or more of claims 22 to 26, characterized in that the braking force exerted on the thread (F) is coordinated by varying the radius of the core (12 '; 13').